PetScience Flealine by Virbac for medium-size dogs is a fast-acting, longer lasting topical flea treatment. It will treat, prevent and control infestations of fleas on large dogs (20kg to 40kg). Each 2.68ml pipette is active on dogs for up to 8 weeks. Each pack comes with 2 pipettes. In times of high flea infestation, or in the treatment and control of flea allergy dermatitis (FAD), a monthly application is recommended.